In a Cloudlinux environment, when trying to switch accounts by using the su command, you are presented with this error:
su: cannot create child process: Resource temporarily unavailable
This usually means that CageFS has not yet been enabled for that user and as a result shell access to that user's environment is not yet available.
CageFS needs to be enabled first with this command:
/usr/sbin/cagefsctl --enable cptest
Updating users ...
And then you can confirm that su is working again by running this command:
[07:31:03 dev root@host ~]cPs# su cptest
[07:31:13 dev cptest@host /root]cPs#